Needle device with activation force limiter

ABSTRACT

A medical instrument having an aspiration needle, handle device and an actuation force limiter. The actuation force limiter provides an active or passive force release mechanism that keeps the force from overpowering operation of the needle.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Needle aspiration devices, such as transbronchial needle aspiration (TBNA) devices, are used to collect samples from target tissue, such as tumors and nodules, for analysis. Activation of a needle requires a distal force applied by an operator interacting with a handle of the device. The distal end of the needle may deflect or buckle if the applied activation force exceeds the translational strength of the needle, thus reducing its effectiveness.

SUMMARY

The present invention provides an example medical instrument for sampling tissue. The example medical instrument includes a handle that controls the force required for a user to activate the needle and provides an active or passive force limiting device.

An exemplary medical device includes a needle having a distal end and a proximal end. The distal end includes a piercing tip and the proximal end includes a shaft section. The device also includes a longitudinal force release mechanism and a handle that includes a handle body having a lumen and a needle actuator. The needle actuator includes an actuator section located at a proximal end of the needle actuator and a shaft section slidably received within the handle body. The shaft section of the needle actuator includes a distal end and a proximal end. The proximal end of the shaft section is connected to the actuator section. The longitudinal force release mechanism allows distal forces below a predefined threshold value applied to the actuator section to transmit to the piercing tip of the needle.

In one aspect of the invention, the longitudinal force release mechanism is configured to at least maintain any distal force applied to the needle actuator that is transmitted to the piercing tip of the needle to be at a value less than the predefined threshold value.

In another aspect of the invention, the longitudinal force release mechanism includes a portion incorporated as part of the shaft section of the needle. The portion is configured to buckle, such that any applied distal force stays below the predefined threshold value. Types of buckling includes Euler buckling, sheer crimping or face sheet wrinkling.

In still another aspect of the invention, the longitudinal force release mechanism includes a radially flexible feature incorporated into the shaft section of the needle actuator and a counterpart feature located on the shaft section of the needle. Contact between the counterpart feature and the radially flexible feature is maintained when a proximal force is applied to the needle actuator or when a distal force that is below the predefined threshold value is applied to the needle actuator. The radially flexible feature and the counterpart feature disengage from each other when the applied distal force becomes greater than the predefined threshold value.

In yet another aspect of the invention, the radially flexible feature includes a protrusion that extends into a lumen of the shaft section of the needle actuator. The counterpart feature includes an annular groove formed around at least a portion of a circumference of an outer surface of the shaft section of the needle. The annular groove is configured to receive the protrusion. The protrusion and the annular groove allow for disengagement when the applied distal force is greater than the predefined threshold value. At least one of materials or surface friction properties between the protrusion and the annular groove are selected to allow for disengagement when the applied distal force is greater than the predefined threshold value.

In a further aspect of the invention, the radially flexible feature includes a groove. The counterpart feature includes a protrusion formed around at least a portion of a circumference of an outer surface of the shaft section of the needle. The groove is configured to receive the protrusion. The shapes of the protrusion and the annular groove are configured to allow for disengagement when the applied distal force is greater than the predefined threshold value. At least one of materials or surface friction properties of the protrusion and the annular groove are selected to allow for disengagement when the applied distal force is greater than the predefined threshold value.

In still a further aspect of the invention, the predefined threshold value is based at least on properties of the tip of the needle.

Further features, advantages, and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the drawings:

FIG. 1-1 illustrates an side view of an aspiration device in a deactivated state in accordance with principles of the present invention;

FIG. 1-2 illustrates an side view of the aspiration device of FIG. 1-1 in an activated state in accordance with principles of the present invention;

FIG. 2 illustrates a cross-sectional view of the aspiration device of FIG. 1-1;

FIG. 3 illustrates a perspective side view of an active release mechanism of the aspiration device of FIG. 2 in a preassembled configuration;

FIG. 4 illustrates a perspective view of a deflecting/flexible portion of the active release mechanism of FIG. 3;

FIG. 5 illustrates a cross-sectional view of a portion of the needle actuator and the needle shaft of FIG. 3;

FIG. 6-1 illustrates an exemplary passive release mechanism;

FIG. 6-2 illustrates an exemplary passive release mechanism;

FIG. 6-3 illustrates an exemplary passive release mechanism; and

FIG. 7 illustrates a graph of needle loading relative to the active and passive release mechanisms shown in the previous figures.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

FIGS. 1-1 and 2 illustrate an example needle aspiration device 20 (e.g., transbronchial needle aspiration (TBNA) device) in a deactivated position and FIG. 1-2 illustrates the device 20 in an activated position. The device 20 includes a handle having a handle body 26, a needle actuator 28, a stylet knob 30 and a Luer component 32. The handle body 26 is attached to a proximal end of a sheath 34. The needle actuator 28 includes a shaft portion 36 coupled to a handle portion 38. The needle actuator 28 receives and makes contact with a proximal end of a needle 40 that is slidably received within the sheath 30. An active release mechanism 100 is incorporated into the interface between the needle actuator 28 and the needle 40 and/or a passive release mechanism (not shown) is incorporated into a portion of a shaft of the needle 40 proximal from a distal tip of the needle 40. The stylet knob 30 is attached to a proximal end of a stylet 46 that is slidably received within the needle 40. A distal end of a Luer component 32 is attached to a cavity of the handle portion 38 of the needle actuator 28.

In the deactivated position, the distal end of the needle 40 is retracted within the sheath 34 (FIGS. 1-1 and 2). In the activated position, the distal end of the needle 40 is exposed beyond the distal end of the sheath 34 (FIG. 1-2).

The shaft portion 36 is slidably received within a cavity (i.e., lumen) of the handle body 26. At a proximal end of the cavity of the handle body 26 is an annular groove that receives at least a portion of an O-ring. The O-ring keeps the shaft portion 36 from being easily removed from the handle body 26.

A user initiates needle activation by applying a distal force to the handle portion 38 of the needle actuator 28 without applying the distal force to the handle body 26. If the distal force exceeds a predefined threshold (e.g., pre-determined load; FIG. 7), the active or passive release mechanisms are activated causing a lease of or a reduction of the applied distal force.

FIGS. 3, 4 and 5 show various views of at least part of the active release mechanism 100. FIG. 3 shows the active release mechanism 100 before assembly. In one embodiment, the active release mechanism 100 includes a proximal end of the needle 40 that is slidably received within a distal end of the shaft portion 36. The distal end of the shaft portion 36 includes a flexible engagement member 144. The flexible engagement member 144 is attached at its proximal end to a body of the shaft portion 36. Edges of the flexible engagement member 144 are defined by longitudinal slats 146 and 148 that separate the edges of the flexible engagement member 144 from the rest of the shaft portion 36. A distal end of an interior side of the flexible engagement member 144 includes a slot engaging protrusion 150. The slot engaging protrusion 150 includes a leading edge 160 and a trailing edge 162. The leading edge 160 includes a normal vector that is not parallel to a longitudinal axis of the needle 40. The trailing edge 162 includes a normal vector that is approximately parallel to the longitudinal axis of the needle 40.

A proximal end of the needle 40 includes an annular groove 152 configured to receive the slot engaging protrusion 150 of the flexible engagement member 144. The annular groove 152 includes a leading edge 156 configured to engage with the leading edge 160 of the slot engaging protrusion 150. The annular groove 152 also includes a trailing edge 154 configured to engage with the trailing edge 162 of the slot engaging protrusion 150. In one embodiment, the normal vectors of the trailing edges 154, 162 are parallel to a longitudinal axis of the needle 40. The normal vectors for the trailing edges 154, 162 may not be parallel to the longitudinal axis of the needle 40, as long as when the trailing edges 154, 162 make contact with each other, they allow a proximal force applied to the needle actuator 28 to move the needle proximally.

In one embodiment, the normal vectors of the leading edges 156, 160 are not parallel to the longitudinal axis of the needle 40. The angular value for the difference between the normal vectors of the leading edges 156, 160 and the longitudinal axis of the needle 40 is chosen to allow the slot engaging protrusion 150 slide out of the annular groove 152, when a predefined distal force (i.e., the threshold value (e.g., pre-determined load; FIG. 7)) has been applied to the needle actuator 28.

In one embodiment, surfaces of the leading edges 156, 160 are chosen to exhibit a predefined amount surface friction between the leading edges 156, 160. The distal force needed to overcome the surface friction is equivalent to the threshold value (e.g., pre-determined load; FIG. 7).

In operation, a user engages the handle portion 38 and applies a force in the distal direction in order to drive the needle 40 out of the sheath 34 and into target tissue for aspirating a tissue sample. The angular value for the leading edges 156, 160 and/or flexibility in the radial direction of the flexible engagement member 144 are selected such that when the distal force becomes greater than a predefined actuation force maximum, the slot engaging protrusion 150 will disengage from the annular groove 152. Disengagement of the slot engaging protrusion 150 from the annular groove 152 disengages or reduces the distal force applied to the handle portion 38 from translating to the needle 40.

After disengagement of the slot engaging protrusion 150 from the annular groove 152, re-engagement can occur simply by retracting the shaft portion 36 until the slot engaging protrusion 150 re-engages with the annular groove 152 with the trailing edges 154, 162 making contact.

FIGS. 6-1, 6-2 and 6-3 show cross-sectional views of various needle shafts displaying the passive release mechanism. These passive release mechanisms are implemented as various buckling modes of the shaft of the needle 40 proximal from a tip of the needle 40. In one embodiment, the shaft of the needle 40 is implemented with a buckling feature within the handle body 26 of the needle aspiration device 20 and the proximal end of the shaft of the needle 40 is affixed to the needle actuator 28. FIG. 6-1 shows the needle shaft exhibiting Euler buckling. FIG. 6-2 shows the needle shaft exhibiting sheer crimping. FIG. 6-3 shows the needle shaft exhibiting face sheet wrinkling. These buckling features of the shaft are configured to be activated once the distal activation force exceeds a predefined maximum threshold value (e.g., pre-determined load; FIG. 7). Once one of the buckling occurs, a distal force is still applied to the distal end of the needle, however the force is below a previously determined needle tip failure value.

In one embodiment, once the distal activation force drops below the predefined maximum threshold value, the needle shafts may return to their pre-non-buckled state. This allows for repeat needle activation.

FIG. 7 illustrates a load versus displacement graph of activation force is applied to the needle systems described above. The predetermined load value is a value less than a value that would cause failure of the needle tip.

EMBODIMENTS

A. A medical device comprising: a needle having a distal end and a proximal end, the distal end comprises a piercing tip and the proximal end comprises a shaft section; a handle comprising: a handle body having a lumen; and a needle actuator comprising: an actuator section located at a proximal end of the needle actuator; and a shaft section slidably received within the handle body, the shaft section of the needle actuator having a distal end and a proximal end, the proximal end of the shaft section is connected to the actuator section; and a longitudinal force release mechanism configured to allow distal forces below a predefined threshold value applied to the actuator section to transmit to the piercing tip of the needle.

B. The medical device of A, wherein the longitudinal force release mechanism is configured to at least maintain any distal force applied to the needle actuator that is transmitted to the piercing tip of the needle to be at a value less than the predefined threshold value.

C. The medical device of A or B, wherein the longitudinal force release mechanism comprises: a portion incorporated as part of the shaft section of the needle, the portion is configured to buckle, such that any applied distal force stays below the predefined threshold value.

D. The medical device of C, wherein types of buckling comprises at least one of Euler buckling, sheer crimping or face sheet wrinkling.

E. The medical device of A or B, wherein the longitudinal force release mechanism comprises: a radially flexible feature incorporated into the shaft section of the needle actuator; and a counterpart feature located on the shaft section of the needle.

F. The medical device of E, wherein the contact between the counterpart feature and the radially flexible feature is maintained when a proximal force is applied to the needle actuator or when a distal force that is below the predefined threshold value is applied to the needle actuator, wherein the radially flexible feature and the counterpart feature disengage from each other when the applied distal force becomes greater than the predefined threshold value.

G. The medical device of E or F, wherein the radially flexible feature comprises a protrusion that extends into a lumen of the shaft section of the needle actuator, wherein the counterpart feature comprises an annular groove formed around at least a portion of a circumference of an outer surface of the shaft section of the needle, the annular groove is configured to receive the protrusion.

H. The medical device of G, wherein shapes of the protrusion and the annular groove are configured to allow for disengagement when the applied distal force is greater than the predefined threshold value.

I. The medical device of G or H, wherein at least one of materials and surface friction properties between the protrusion and the annular groove are selected to allow for disengagement when the applied distal force is greater than the predefined threshold value.

J. The medical device of E or F, wherein the radially flexible feature comprises a groove, wherein the counterpart feature comprises a protrusion formed around at least a portion of a circumference of an outer surface of the shaft section of the needle, the groove is configured to receive the protrusion.

K. The medical device of J, wherein shapes of the protrusion and the annular groove are configured to allow for disengagement when the applied distal force is greater than the predefined threshold value.

L. The medical device of J or K, wherein at least one of materials or surface friction properties of the protrusion and the annular groove are selected to allow for disengagement when the applied distal force is greater than the predefined threshold value.

M. The medical device of any of A-L, wherein the predefined threshold value is based at least on properties of the tip of the needle.

The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. 

What is claimed is:
 1. A medical device comprising: a needle having a distal end and a proximal end, the distal end comprises a piercing tip and the proximal end comprises a shaft section; and a handle comprising: a handle body having a lumen; and a needle actuator comprising: an actuator section located at a proximal end of the needle actuator, wherein the actuator section is slidably received within the handle body, wherein the actuator section comprises: a shaft portion; and a flexible engagement member having a first end attached to the shaft portion and a second end opposite the first end, the second end having a protrusion, wherein the flexible engagement member is configured to be flexible thus allowing the protrusion to move in a direction perpendicular to a longitudinal axis of the actuator section; and a shaft section slidably received within the handle body, the shaft section of the needle actuator having a distal end and a proximal end, the distal end being connected to the shaft section of the needle, wherein the shaft section comprises a groove configured to receive the protrusion; and wherein the protrusion maintains engagement with the groove while a distal force applied to the actuator section remains below a predefined threshold value, when the distal force is greater than the predefined threshold value, the protrusion disengages from the groove by overcoming a frictional force between the protrusion and the groove.
 2. The medical device of claim 1, wherein the engagement between the protrusion and the groove is configured to transmit any distal force applied to the needle actuator that is transmitted to the piercing tip of the needle to be at a value less than the predefined threshold value.
 3. The medical device of claim 2, wherein the protrusion comprises: a radially flexible feature incorporated into the shaft section of the needle actuator.
 4. The medical device of claim 1, wherein at least one of materials and surface friction properties between the protrusion and the groove are selected to allow for disengagement when the applied distal force is greater than the predefined threshold value.
 5. The medical device of claim 1, wherein the predefined threshold value is based on translation strength of the needle.
 6. The medical device of claim 1, wherein the protrusion and the groove are configured to reengage after disengagement and after proximal movement of the actuator section relative to the shaft section of the needle actuator.
 7. A medical device comprising: a needle having a distal end and a proximal end, the distal end comprises a piercing tip and the proximal end comprises a shaft section; and a handle comprising: a handle body having a lumen; and a needle actuator comprising: an actuator section located at a proximal end of the needle actuator, wherein the actuator section is slidably received within the handle body, wherein the actuator section comprises: a shaft portion; and a flexible engagement member having a first end attached to the shaft portion and a second end opposite the first end, the second end having a protrusion, wherein the flexible engagement member is configured to be flexible thus allowing the protrusion to move away from a longitudinal axis of the actuator section; and a shaft section slidably received within the handle body, the shaft section of the needle actuator having a distal end and a proximal end, the distal end being connected to the shaft section of the needle, wherein the shaft section comprises a groove configured to receive the protrusion; and wherein the protrusion maintains engagement with the groove while a distal force applied to the actuator section remains below a translation strength value of the needle, when the distal force is greater than the translation strength value, the protrusion disengages from the groove by overcoming a frictional force between the protrusion and the groove. 